Ever hear a sudden, loud noise like a nearby gunshot, and instantly get snapped out of whatever it is you were doing and for awhile afterward your body feels kind of buzzed? It also seems you can see and feel everything around you while the effect lasts. It's happened to me a few times, and recently I came across an explanation. It's called the orientation reaction.
In 1927 CE Ivan Pavlov first documented this effect while conducting tests on his famous dogs.
In Pavlov's words, "It is this reflex which brings about the immediate response in man and animal to the slightest changes in the world around them, so that they immediately orientate their appropriate receptor organ in accordance with the perceptible quality in the agent bringing about the change, making full investigation of it."
The orientation reaction occurs for a number of seconds in response to unfamiliar stimulus. Subjects exhibit the following physiological changes at the moment of the stimulus and for several seconds afterwards.
In short, the subject’s body prepares for both fight and flight
until the source of the stimulation can be resolved. Repeated exposure to the same stimulus results in habituation
and reduction of the response.
Another Russian psychologist named Sokolov in 1961 showed in the early 1960s that in humans the orientation reaction causes lower sensory thresholds.
The canine orientation reaction was captured for popular culture most famously in the RCA logo. Most everyone can recognize the physical expression as Nipper hears his master’s voice coming from the bizarre gramophone shape before him.